    Patent Document 1: JP-A 2006-104448    Patent Document 2: JP-A 2003-159696    Patent Document 3: JP-A 2003-210957    Patent Document 4: JP-A 2004-49957    Non-Patent Document 1: “Microreactor: Synthesis Technology in New Age”, supervised by Junichi Yoshida, CMC Publishing Co., Ltd.    Non-Patent Document 2: X. F. Zhang, M. Enomura, M. Tsutahara, K. Takebatashi, M. Abe “Surface Coatings International Prat B: Coatings Transactions,” Vol. 89, B4, 269-274, December 2006
A microreactor or a micromixer has been provided as a fluid processing apparatus using a fine flow path or a fine reaction container. There is possibility that the microscopic reaction field given by such an apparatus could exert a substantial influence on chemical reactions carried out in beakers and flasks so far (see Non-Patent Document 1).
A typical micromixer and microreactor are provided with a plurality of microchannels of about several ten μm to several hundred μm in diameter and with mixing spaces connected with the microchannels, and in this micromixer and microreactor, a plurality of solutions are introduced into the mixing spaces through a plurality of flow paths called microchannels, thereby mixing the plurality of solutions or allowing a chemical reaction together with mixing. For example, Patent Documents 1 to 3 disclose those structures as microreactors and micromixers. In any of these microreactors and micromixers, at least two types of solutions are passed through fine microchannels respectively and fed as laminar flows having a very thin section, into a mixing space, and in this mixing space, two solutions are mixed and/or reacted.
There are many advantages in microreactors and systems thereof, but as the micro flow path diameter is decreased, a pressure loss is inversely proportional to the biquadrate of the flow path. That is, such high feeding pressure is necessary that a pump making possible to feed a fluid cannot be available. In the case of a reaction accompanied by separation, there is a problem that a microwave flow path is blocked by clogging of a flow path with a product or bubbles the reaction generates. Further, it is also a problem that since the reaction fundamentally depends on speed of molecular diffusion, a microscopic space is not effective or applicable to every reaction, and actual attempts of the reaction are required by trial and error, then good results are selected. Scaling up has been coped with a method of increasing the number of microreactors, that is a numbering-up system, but the number of microreactors which can be comprised is limited to several dozen, thus inherently aiming exclusively at products of high value. The increase in the number of devices leads to an increase in the absolute number of failure causes, and when the problem of clogging or the like actually occurs, it can be very difficult to detect a problem site such as a failure site.
As shown in an apparatus in Patent Document 4 filed by the present applicant, there is an apparatus wherein a fluid containing a material to be processed is introduced between the processing surfaces, at least one of which rotates relative to the other, and which are capable of approaching to and separating from each other, and at least another fluid containing a material to be processed is introduced between the processing surfaces from another flow path that is independent of the flow path for introducing the first fluid and is provided with an opening leading to the processing surfaces, whereby the two fluids are reacted by mixing and stirring between the processing surfaces. By using this apparatus, improvement on speed of temperature homogenization, improvement on speed of homogenization of concentration, and reduction in processing time in support of molecular diffusion, which have been attempted by conventional micro reactors, can be achieved more effectively than ever.
However, even if the apparatus with the mechanism described above is used to process between the processing surfaces, substances to be separated would cause clogging in the vicinity of the opening in the processing surfaces by a reaction accompanied by separation at high reaction speed, and thus the reaction may be interrupted. Further, a spiral laminar flow that is a fluid formed between the processing surfaces is disrupted thus often failing to attain intended favorable results such as homogeneous processing and formation of microparticles.
In the case of processing with the apparatus shown above, the processing surfaces provided with a depression are rotated whereby a fluid in the depression moves at a certain speed toward the end of the depression in the direction of outer periphery. Then, the fluid sent to the end of the depression further receives pressure from the depression in the direction from inner periphery, finally turning to pressure in the direction of separating the processing surfaces, simultaneously being introduced between the processing surfaces. The processing surfaces provided with a depression are rotated thereby generating a force exerted in the direction of separating the processing surfaces and introducing the fluid between the processing surfaces, the effect of which is called a micropump effect. The direction of introducing the fluid caused by the micropump effect does not coincide with the direction of rotation of the processing surfaces. However, where the reaction actually occurs between the processing surfaces, that is, in the flow of the fluid between the processing surfaces after the flow in the introducing direction caused by the micropump effect is cleared, the flow of a spinal laminar flow in the rotation direction is shown, as the numerical simulation results (Non-Patent Document 2) indicate. That is, there exists where the flow direction caused by the micropump effect is converted into the rotation direction in the processing surfaces. In its vicinity, an eddy or the like may be formed to cause flow disturbance.
Further, when the depression arranged on the processing surfaces for producing the micropump effect is provided too deep, the vertical micropump effect becomes too large in the radial direction, and the micropump effect extends in the radial direction and further is accompanied with pulsations, so the formation of a uniform thickness between the processing surfaces may be prevented. This also applies to the case wherein a total area of the depressions in a horizontal direction is too large against the processing surfaces. When a total area of the depressions in a horizontal direction is too small against the processing surfaces, effective introduction of the fluid into the processing surfaces from the center of the processing surfaces cannot be achieved.
However, it is not enough to solely consider the volume given by determining the total area and depth of the depressions. An average flow of a spiral and laminar one between the processing surfaces cannot be secured without a method of locating the depressions, the whole volume of which are equally divided and arranged in the center of the processing surfaces, and introducing a fluid between the processing surfaces evenly.
Further, a problem like the above will be caused without providing a specific shape with the depression in order to introduce a fluid evenly.
Favorable results intended in uniform processing and formation of microparticles between the processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other, cannot be obtained without solving these problems.
Further, the present inventors have examined introduction of a few kinds of other fluids from another fluid path independent of a flow for introducing a fluid by the micropump effect from the center of processing surfaces when the following chemical reaction is carried out between the processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other.A+B→C  (1)C+D→E  (2)
When the reactions in the reaction formulae above are carried out between processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other, the order is as follows: First, a fluid containing a material A to be processed is introduced by the micropump effect between the processing surfaces. Then, a fluid containing a material B to be processed is introduced between the processing surfaces through a flow path independent of the flow path for introducing the fluid containing a material A to be processed. The material A is reacted with the material B to form a product C. Further, a material D to be processed is introduced into a flow path independent of the flow path for introducing the fluid containing a material A to be processed, and the flow path for introducing the fluid containing a material B to be processed. The product C is reacted with the material D to form a product E.
In a case where various materials to be processed as described above are reacted with one another by simultaneously introducing into the processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other, production of the final processed material E is adversely affected when each of the flow paths independent of the flow for introducing the fluid containing a material A to be processed is arranged in arbitrary places. That is, there is a problem that in spite of the fact that A, B, C and D are originally reacted in this order to give the product E, this order may not be followed such that the reaction A+B+C→the product E, the reaction of which is not due to the original reaction process, occurs to produce a different substance. In contrast, the processed materials may not be efficiently contacted with one another, and thus the reaction may not be carried out, or a substance in poor production such as a processed material B′ may be generated, or the yield of the product E may be decreased, so that there is a problem that the objective particle diameter, crystal form, and molecular structure may not be obtained. When the processed material after being processed needs to be, for example, temperature-controlled, its mechanism is not concretely established, so there is a problem that the material is subjected once to change in temperature.
Based on the phenomenon described above, the present invention further improves the apparatus in Patent Document 4 and provides a fluid processing apparatus and a processing method capable of carrying out more stable and uniform processing.
That is, in an apparatus wherein a material to be processed is processed between processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other, when a fluid containing a material to be processed is introduced between the processing surfaces by a micropump effect from the center of the rotating processing surfaces, and when at least another fluid containing a material to be processed is introduced between the processing surfaces from another flow path that is independent of the flow path for introducing the first fluid and is provided with an opening leading to the processing surfaces, the direction and angle of introduction and the diameter of the opening are allowed to be in a specific range, and simultaneously, the place and the number of the introduction are determined depending on the objective processing form. Further, the range of the depth, area, shape and numbers of depressions arranged on the processing surfaces is set so that the problem described above can be solved. Further, the mechanism in which a fluid containing a product obtained between the processing surfaces is charged directly into an external fluid of processing members is arranged thereby solving the above problem.
On the other hand, when a fluid is processed between processing surfaces in the apparatus with the mechanism shown in Patent Document 4, improvement on speed of temperature homogenization, improvement on speed of homogenization of concentration, and reduction in processing time in support of molecular diffusion, which have been attempted as described above, cannot be completely achieved if the processing with stirring and mixing is carried out only with a spiral laminar flow between the processing surfaces. Accordingly, the present inventor has extensively studied and found that in an apparatus wherein a fluid containing a material to be processed is introduced between processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other, and at least another fluid containing a material to be processed is introduced between the processing surfaces from another flow path that is independent of the flow path for introducing the first fluid and is provided with an opening leading to the processing surfaces, whereby the processing is done by mixing and stirring between the processing surfaces, a process between the processing surfaces can be carried out more efficiently and effectively than ever by generating a flow perpendicular to the processing surfaces, in addition to a spiral laminar flow between the processing surfaces.
Based on the phenomenon described above, the present invention further improves the apparatus in Patent Document 4 and provides a fluid processing apparatus and a processing method capable of carrying out more stable and uniform processing by generating, between the processing surfaces, a flow perpendicular to the processing surfaces.